In the mid-70s, when The Muppet Show premiered, it was still fairly common for movie and TV show titles to be handlettered, as this one was. Most of the letters have the thick, bracketed serifs characteristic of ITC Bookman, which was very much in vogue in the 70s. The title is full of intentional idiosyncrasies, like the Garamond-esque T, the Belwe-like e, and the wocka-wocka h.